Composition for forming silicon-containing resist underlayer film and patterning process

Abstract

A composition for forming a silicon-containing resist underlayer film contains at least one or more kinds of a quaternary ammonium salt shown by the following general formula (A-1), and a thermally crosslinkable polysiloxane (Sx), where Ar1 represents an aromatic group having 6 to 20 carbon atoms, or a heteroaromatic group having 4 to 20 carbon atoms. R11 represents an alkyl group, alkenyl group, oxoalkyl group, or oxoalkenyl group having 1 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group or aryloxoalkyl group having 7 to 12 carbon atoms. Some or all of hydrogen atoms of these groups are optionally substituted. Z− represents an organic or inorganic anion as a counterion of the quaternary ammonium cation. An object is to provide a silicon-containing resist underlayer film having high effect of suppressing ultrafine pattern collapse and appropriate etching rate in multilayer resist methods.

Description

TECHNICAL FIELD[0001]The present invention relates to a composition for forming a silicon-containing resist underlayer film, and a patterning process using the composition.BACKGROUND ART[0002]As Large-Scale Integrated circuits (LSIs) advance toward higher integration and higher processing speed, miniaturization of pattern size is rapidly progressing. Along with this miniaturization, the lithography technology has achieved formation of fine patterns by shortening the wavelength of a light source and by selecting a proper resist composition corresponding to the shortened wavelength. The main factor of this achievement is a positive photoresist composition used as a monolayer. This monolayer positive photoresist composition allows a resist resin to have not only a skeleton that possesses etching resistance against dry etching with chlorine- or fluorine-based gas plasma, but also a switching mechanism that makes an exposed part soluble. Thereby, after a pattern is formed by dissolving t...

AI Technical Summary

Benefits of technology

The invention is a composition that helps create a silicon-containing resist underlayer film. This film helps create ultrafine upper layer resist patterns without collapse and has a good pattern profile. It also has excellent dry etching selectivity relative to a resist upper layer film, an organic film, or a hard mask. This composition can help transfer a photoresist pattern from a silicon-containing resist underlayer film to an organic film or hard mask by dry etching. Additionally, the silicon-containing resist underlayer film has sufficient etching rate, making it easy to remove after patterning. This invention is useful for creating fine patterns.

Problems solved by technology

In addition, if the photoresist film is pattern-developed by using a developer, what is called an aspect ratio thereof becomes so large that a problem of the pattern collapse occurs.

In practice, however, there is no dry etching method capable of providing an absolute etching selectivity between the photoresist film and the substrate to be processed.

Thus, there have been problems that the resist film is also damaged and collapses during the substrate processing, and the resist pattern cannot be precisely transferred to the substrate to be processed.

This shift actually accelerates the etching rate under dry etching condition for processing the substrate, and recent photoresist compositions having high resolution tend to have rather low etching resistance.

If the etching rate is insufficient, this increases a possibility that the residue derived from the silicon-containing film stays and causes defect, or that longer etching treatment is required, bringing about problems such as damaging the substrate to be processed.

On the other hand, ultrafine patterns have such small contact areas that the patterns quite easily collapse.

Suppressing such pattern collapse is an enormous challenge.

The subsequent substrate processing failure causes serious problems.

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